Clutch control mechanism



w. s WATTS CLUTCH CONTROL MECHANISM April 25,,1939.

Origin'ajzl Filed Oct. 20, 1935 2 Sheets-Sheet l INVENTOR W/u #W 6. M47715 BY 1s:

ATTORNEY April 25, 1939. w; s WATTS 2,156,136

CLUTCH CONTROL MECHANISM Original Filed Oct 20, 1955 2 Sheets-Sheet 2 INVENTOR Mu wd M4775 a:

ATTOR EY sirable fluctuation of the valve.

Patented Apr. 25, 1939 CLUTCH CONTROL MECHANISM William S. Watts, South Bend, 1nd., assignor to Bendix Aviation Corporation; Ind., a corporation of Delaware- Soilth Bend,

Original application October '20, 1933, Serial No.

694,437.- Divided and this application December 30,1936, Serial No. 118,369

.4 Claims. (or. 192- 01)- v This invention relates in general to power operated clutch control mechanism for an automotive 'vehicle, and in particular to means for regulating the clutch engaging operation of the manifold vacuum operated motor operably conclutch.

One of the'well-knowncommercial types of clutch motors or clutch operators comprises a double-ended cylinder housing a reciprocable piston operably connected to the clutch pedal," 29 wherein there is provided a three-way valve or so-ca'lled dump'valve constituting part of the aforementioned control valve mechanism. The control valve is preferably operated by the accelerator in such manner as to alternately connect one end of the cylinder with the intake manifold of the engine and to the atmosphere to thereby initiate the clutch disengaging and engaging operations of the motor. Other valve means are provided for controlling the efllux of 30 air from the other end of the cylinder to vary the loading ofthe clutch plates. One feature of the present invention is directedto the constru'c tion and mode of operation of the latter valve means. V j

To this endthere is provided a pressure. dif-. ferential operated bleed valve incorporated in the vent from the last-mentioned end;of. the cylinder, the valve and the means for operating the same being so constructed and so intercon- 40 nected with the engine of the vehicle as to 'operate in accordance withthe degree of vacuum developed by a venturi mounted within the in;

I take'duct of a down-draft carburetonl This is an important feature, since'heretofore the bleed valve hasbeen operated by means, such for example as the manifold vacuum, which'is'sub- Ject to extraneous variables resulting in unde- The prior-art relating to controlling means'for'the bleed valve does not suggest clutch operating mechanism inloading is proportional to the engine torque.

I valve mechanism of Figure 1.

Yet another object of the invention is to provide apressurediflerential actuated clutch operator, wherein the throttle operating means of the.

vehicleserves as a common control means for the,

throttle and the control valve mechanism of the clutch operator. To this end there is provided a valve mechanism comprising a three-way or dump valve for initiating the clutch disengaging and engaging operations of the clutchoperator, the said valve mechanism being controlled by the operation of the throttle. In the embodiment disclosed, there is also provided the bleed valve referred to above, the same comprisinga'power operated relay valve of the balanced type ,to, provide a follow-up control of the clutch operatoriin effecting its clutch engaging operation. -,Other objects of the invention and desirable details of construction and combinations of parts, will become apparent from thefollowing descrip-. tion of a preferred embodiment, which description is taken in conjunction with the accompanying drawings, in which: I

Figure Us a diagrammatic view of a preferred embodiment of the clutch control mechanism constituting the present invention;

Figure 2 is a sectional view of the bleed'valve mechanism of Figure 1;

Figure 3 is a sectional view of the clutch operating pressure differential operated motor d1s-. closed in Figure 1; and r f Figure '4 is a sectional view oi? the three-way 'Referring now to the preferred embodiment of the invention disclosed diagrammatically in, Figure 1, there is provided a1 clutch motor l0 comprising a double-ended-cylinder l2, prefera-j -bly pivotally mounted to a fixed portion-of the vehicle, said cylinder housing a"reoiprocable piston I4 constituting the power, element of the. motor and operably connected to 2V clutch pedal 7 l6 by linkage l8. The clutchlpedal, serves to operate a conventional clutch comprising driving the connection 24 providing a means whereby the clutch pedal may ,be] depressed without affecting the power means. A left compartment 28 of the cylinder I2 is alternately evacuated and vented to successively initiate a disengage- 1 ment of-theclutch and an engagement thereof by means of a conduit-30 connectingv the clutch motor with the atnipsphernnd with an intake -or retainers 58 and 58.

housed between a cup-shaped washer 62 and the manifold 32 of an internal-combustion engine, not shown, a three-way valve 84 being incorporated in the conduit to effect the aforementioned control. The valve 34 is arranged to be operated by an accelerator 38, the latter also operating a throttle valve 38 of the engine, a linkage 40 interconnecting these parts. Springs 42 and 44 serve to return the throttle valve 38 and accelerator 38 to their respective ofl!" positions upon release of the accelerator. No claim is made to the aforementioned construction, for the same is disclosed and claimed in the patent to Ross I. Belcia, No. 1,470,272, dated October 9, 1923.

The invention is, in part, directed to valve means 46 for regulating the eiilux of air from a right compartment 48 of the cylinder I2 to thereby control the engagement-mt the clutch. The

valve structure is disclosed in 'detail in Figure 2 and includes a casing comprising interconnected members 50 and 52, said members housing therebetween a diaphragm member 54 secured in position at its peripheral edge between the casin members. The valve provides chambers A and B to receive respectively the air from the comr partment 48 and the air from a source to be described hereinafter. To the center of the diaphragm 54 are secured cup-shaped washers A metal spring 80 is washer 58, the spring serving to force-the diaphragm 54 into engagement with a raised or land portion 84, constituting a part of the lower casing section 52. A stop member. 88 is adjustably mounted in the casing member 50 and abuts the cup-shaped washer 62, providing a means to vary the compression of the spring 88. The diaphragm 54 and members 58 and 58 are clamped together by a bolt 88 and a nut I8. As indicated above, the diaphragm is normally seated, with the engine idling, upon the raised portion 84 integral with the casing member, that portion of the diaphragm contacting the raised portion 64 constituting, together with said latter portion, a bleed or blow-oil valve, referred to in greater detail hereinafter. A port 12 in the casing member 58 is connected, by means of a conduit 14, with a Venturi structure I8 mounted at the air intake side of a down-draft type of carburetor 18. The chamber A of the bleed valve mechanism is connected,.via a valve port, with the compartment 48 of the cylinder l2 by means of a conduit 82. To a port 84 in the casing member 52 is secured an inertia operated cut-of! valve 88, said mechanism not being claimed herein, inasmuch as the same is disclosed and described in the application of Harold W. Price,

Serial No. 622,513, filed July 14, 1932.

Referring now to the operation of the above-' described mechanism, with release of the accel- -erator the throttle is closed toidle the engine,

thereby producing, by virtue oi the pumping action of the engine pistons, a manifold vacuum of some twenty inches of mercury at sea level.

The three-way valve 34 is, with the release of the accelerator, operated to intercommunicate the manifold with the left compartment 28 of the cylinder l2, a-spool member 88 of the three way valve being moved tothe right, Figures 1 and 4, to effect this connection. The compartment 28 is accordingly partially evacuated, the

atmosphere acting upon the right side of the piston l4, and entering the cylinder via an inuardly opening check valve, serving to move preferably after the valve member 88 has been moved to vent the cylinder, there being provided a lost motion connection 94 in the throttle linkage to accomplish this end.

' .With the venting of the compartment 28, the

conventional clutch spring 86 immediately acts to engage the clutch, the mode of engagement being determined by the mode of eiliux of air from the right compartment 48 of the cylinder 12. The air from the compartment passes rapidly from the cylinder via a slot 88 in the con-- necting rod l8, effecting a relatively rapid movement of the clutch pedal to take up theclearance between theclutchplates. When the piston l4 and connecting rod have moved to such a position that the slot 98 is either covered by the end wall of the cylinder or lies beyond said wall outside the cylinder, air may no longer pass from the cylinder via the slot: the air, however, continues to rapidly flow from the compartment 48,

via the conduit 82, thence into the chamber A of 1 the valve 46, through said valve, which is at this time slightly open owing to the superatmospheric pressure in the chamber, and out to the atmosphere via the inertia operated valve 86. The valve spring 88 is of such strength as to be compressed by. the escaping air to open the bleed valve, said valve remaining open howeveronly until the clutch plates have contacted with a predetermined relativelyslight load. When this occurs the relativeiy high gaseous pressure within the compartment 48 of the cylinder automatically drops, to an amount however substantially above the pressure of, the atmosphere, and

the spring automatically acts to seat the bleed valve, this operation being known in the art as a lapping of the valve. Thus, whenever the clutch is being engaged, the plates ,are always initially loaded to a predetermined amount, irre: spective of the worn-infcondition of theclutch facings, said loading depending upon the proportioning of the parts and the strength of the clutch spring and spring 60.

The above-described operation preferably takes place with an opening of the throttle just Sl.l.f'

ficiently to effect an operation of the three-way valve, the parts of the mechanism being adjusted to eifect this result. With a continued depression of the accelerator the throttle is opened to speed upthe engine, resulting in a decrease in pressure in the chamber B acting on the diaphragm 54.

This pressure, together with the super'-atmosis reseated. It will be noted'that the sum of the forces acting to seat the diaphragm 54 and resulting from the additive eflfect of the pressure in the chamber 13 and the spring is substantially equal to the force exerted by the pressure within the chamber A when the system is in equilibrium and the bleed valve is seated, and the pressure in chamber B decreases proportionately with the increase in pressure in chamber A.

Furthermore, in order to unseat the bleed valve the pressure in chamber A must be increased, so that the force resulting from the sum of the loading of the spring 60 and the pressure in chamber B is less than the force exerted by the gas within the chamber A. It therefore follows that the force exerted by the clutch springs at any given instant after the clutch plates have contacted is directly proportional to the pressure in the chamber B, and therefore directly propontional to the degree of opening of the throttle.

The bleed or blow-oil valve is rendered operable by virtue of the evacuation of the chamber B within the valve mechanism. The velocity of air passing through the venturi i6 is effective to draw the air from said chamber through the conduit 14 in accordance with the degree of throttle opening, the latter progressively increasing the air intake via the venturi. Thus the degree of vacuum within the chamber 13 is in-' creased in direct proportion to the degree of throttle opening.

This, however, is exactly the end desired, for the loading of the clutch should be regulated in accordance with the speed of the engine, and the resultant torque of the engine driven clutch plate or flywheel to efleet the desired smooth engagement of the clutch and also obviate any possible stalling of the engine.

With the above-described mechanism there is provided in a relatively simple fluid operated clutch operator or sIo-called automatic clutch the principal advantages of the more complicated centrifugal clutch of the day. Furthermore, it

I should be noted that the balanced valve mechanism suggested provides the much desired follow-up to-lap type of control of the clutch motor. The invention heretofore described is disclosed in my copending application No. 694,437. filed October 20, 1933, this application constituting a division thereof.

While one illustrative embodiment has been described, it is not my intention to limit the scope of the invention to that particular embodiment, or otherwise than by the terms of the appended claims.

I claim:

1. In a clutch control mechanism for an automotive vehicle provided with a clutch, a down. draft carburetor having mounted within the intake duct thereof a venturi, a pressure differential operated motor ,operably connected with the clutch, and control valve mechanism for said motor comprising valve means for controlling the" clutch engaging operation of said motor, said valve means being operative in accordance with the gaseous pressure developed within the aforementioned venturi.

2. In a clutch control mechanism for an automotive vehicle provided with a clutch, a downdraft carburetor having mounted within the intake duct thereof a venturi, a pressure differential operated motor operably connected with the clutch, ..and control valve mechanism for said motor comprising a pressure sensitive valve, fluid transmitting means interconnecting said valve and venturi, and other fluid transmitting means interconnecting said valve and motor.

3. In a clutch control mechanism for an automotive vehicle provided with aclutch and further provided with aventuri mounted within the intake duct of a carburetor, apressure differential operated motoroperably connected with the clutch, and control valve mechanism for said motor comprising a pressure balanced valve,

fluid transmitting means interconnecting said valve and venturi, and other fluid transmitting means interconnecting said valve and motor, said control valve mechanism further comprising a valve operative to initiate the clutch disengaging and engaging operations of said motor.

4. In a clutch control mechanism for an automotive vehicle provided with an intake manifold, a throttle valve, and a clutch, a carburetor mechanism having mounted within the intake duct thereof a venturi, and an accelerator, a doubleended pressure diiferential operated motor operably connected with the clutch, and control valve mechanism for said motor comprising a pres'-. sure sensitive valve, fluid transmitting means interconnecting said valve and venturi, and other fluid transmitting means interconnecting said valve and one of the compartments of said doubleended motor, said control valve mechanism fur ther comprising a valve operative to initiate the clutch disengaging and engaging operations of said motor.

WILLIAM S. WATTS; 

